This is usually 1. If the image data is supposed to be planar, it can be the number of planes. It should be positive in any case.
This value will most likely be 1, indicating that the image data is interleaved. This is how all the know cards expect the image data. But, if another card will expect the data to be planar, you should set this to the number of planes (3 for 24/48-bit data, 4 for 32/64-bit data). LEADTOOLS does not have built-in support for converting to planar data, so you would have to do the color conversion yourself using the RasterImagePaintCallbackFunction.ConvertLineCallback callback.
For an example, refer to RasterPaintDibInfo.